Hiya, can anyone help?

In sheet1 I have a range called table1 in which one column contains a list of reference numbers. In sheet2 I have another list of reference numbers.

I want to determine if the column in sheet2 contains any values that do not exist in sheet1 and if so highlight them. The list in sheet2 does contain duplicates.

On sheet3 I would like a formula to ideally list those missing reference numbers or at least count them so the user can be made aware.